Brake mechanism for washing machine



Aug. 6, 1963 S. L. M MILLAN BRAKE MECHANISM FOR WASHING MACHINE Filed001;. 50, 1961 3 Sheets-Sheet l INVENTOR. STEPHEN L. M MILLAN ATTORNEYAug. 6, 1963 s. L. M MILLAN 3,100,030

BRAKE MECHANISM FOR WASHING MACHINE Filed Oct. 50, 1961 3 Sheets-Sheet 2AGITATE INVENTOR. STEPHEN L. M MILLAN A 32 ATTORNEY Aug. 6, 1963 s. L. MMILLAN BRAKE MECHANISM FOR WASHING MACHINE 3 Sheets-Sheet 3 Filed Oct.30, 1961 SPIN INVENTOR.

FIG. 7

ATTORNEY United States Patent 3,109,030 BRAKE MECHANISM FOR WASHINGMACHHJE Stephen L. McMillan, Wheaten, 11., assignor to General ElectricQompany, a corporation of New York Filed Oct. 30, 1961, Ser. No. 148,6166 Claims. (61. res-6s The present invention relates to brake mechanismsand more particularly to brake mechanisms for use on clothes washingmachines.

It is generally known that with washing machines which operate on theprinciple of utilizing an inner vertical shaft for oscillating acenterpost agitator and an outer coaxial tubular shaft for rotating thespin basket, the basket has a tendency to oscillate sympatheticallyduring agitation, a tendency Which disrupts the normal wash patterns.Various forms of mechanisms have been used to combat this tendency suchas one-way spring clutches and solenoid-operated latching brakes. Ofthese mechanisms, the last-mentioned type has an inherent advantage inthat it effects a second and equally important function, namely, that ofstopping the basket rotation in a matter of seconds on occurrence ofconditions such as de-energization of the motor. Such de-energization ofthe motor may be due to the termination of the spin period, may be dueto the operation of safety switches incident to the lid of the machinehaving been opened, or may be due to the basket having gyratedexcessively. In any event, it is most important that the spin basket bebraked and stopped rapidly, this being of special urgency where thetriggering condition was the opening of the lid by the user, in that theperson opening the lid may intend to reach into the basket. This is apotentially dangerous situation, and an efficient basket brakingmechanism is an effective protection against bodily harm.

In any event, when the motor is de-energized, a posi tive acting brakewill quickly decelerate the basket and will hold the basket stationaryat all times other than motor-spin periods. It is to improvements inthis type of positive acting brakes that the present invention isdirected.

With braking action of the type required, contact must be made between astationary actuating mechanism and a braking device which is rotatedwith the spin basket but capable of rotation relative thereto. Thiscontact must be transmuted into a relationship with the braking device(for example, a housing structure having an internally arranged brakeband) which will cause the braking device to come to an immediate stoprelative to the rotating basket and initiate the braking action todecelerate the rapidly rotating, high-inertia spin basket. The problemswhich result from this braking action are numerous. First, thestationary mechanism must latch into the rotating braking device on onerotation of the spin basket. With the basket rotating at a high speed,the possibility of losing the contact between the parts with consequentabrasion of the parts on one another is quite great. Following the lostcontact, further contact must be made rapidly in order to initiate thebraking action. Further, once the contact has been made, the highinertia of the rotor may tend to develop excessive strains in thelatching members in attempting to halt the rotation of the device in tooshort a period of time. The present invention alleviates thesedifficulties by providing a stationary actuating member which seeks toestablish a latching relationship with the rotating housing structureencompassing the brake band. The brake housing however ofiers only onearea of limited angular extent where initial contact between the latchmechanism and brake band housing can be made. This initial contact isnot an engaging contact in which the brake housing is attempted to bestopped. Instead,

3,100,030 Patented Aug. 6, 1963 there is a cam surface along which thelatch mechanism must be conducted for a finite length of time beforeengagement is made with a portion of the housing. As this engagement isefiected, the brake band rotation is stopped and the spin tub isdecelerated.

The latch mechanism is normally biased toward the plane of the initialcontact area and cannot establish other than surface contact with thebrake housing at any other angular position of the brake housing. Thiscontact once established, is continued for over one half a revolutionbefore the latching engagement with a radially extending brake arm ismade. It is a feature of the invention that the brake arm is not in theplane of the contact area, and can only be reached by the travel of thelatch along the cam surface. Thus, with a brake mechanism embodying thepresent invention, there is always a delay between the time of initialcontact of the latch and the brake and the start of the braking action.By providing this time interval, it is ensured that the abruptengagement which occurs at the start of braking happens only when apositive contact has been effected and ensured between the latch and thebrake band housing portion.

To efiectuate this two-step brake engagement, the present inventionutilizes a braking structure which includes a cylindrical brake band andouter housing about the spin shaft. Within the housing there is provideda latch contacting area of limited angular length extend-ing along thehousing. From this area of contact, an acclivitous cam surface traversesthe brake housing angularly for or more and terminates at a radial stopmember spaced angularly and axially from the area of original contact.The stationary latch member is normally biased in the horizontal planeat the level of the contact area so that when the latch member isimpelled toward the brake housing it can only contact the housing in thecontact area. The member will enter the area and will slide along thecam surface as the housing continues its rotation for a finite timeperiod. At the end of the period of positive con-tact the member engagessaid radially extending stop member to actuate the brake band bringingthe braking structure to a stop and thus initiat ing the braking actionbetween the brake band and the spin shaft.

It is therefore an object of the invention to provide an improvedpositive-acting, braking mechanism for a rotating clothes washingmachine basket.

It is a further object of the invention to provide a brake mechanismwhich attains an initial contact between a stationary member and arotating brake member at only one period in the rotation of the brakeand eifec-ts the brwng action a finite period of time thereafter.

Other objects, features and advantages of the invention will be apparentfrom the detailed description of the presently preferred embodimentsthereof, read in connection with the accompanying drawings in which:

FIG. 1 is a partially sectioned side elevational view of a washingmachine employing the invention;

FIG. 2. is a top plan View partially in section of a first embodiment ofthe braking mechanism of FIG. 1;

FIG. 3 is a side elevational view of the first embodiment of the brakemechanism of FIG. 2;

FIG. 4 is a side sectional elevation viewed along the lines 4-4 of FIG.2;

FIG. 5 is a top plan view partially in section of a second embodiment ofbrake mechanism;

FIG. 6 is a side sectional elevation of the second embodiment viewedalong lines 66 of FIG. 5;

FIG. 7 is a cam development chart of the cam surface of the secondembodiment;

FIG. 8 is a side elevation of the latch arm as used in the secondembodiment; and

FIG. 9 is a schematic wiring diagram applying my principle of operation.

Referring now to FIG. 1 of the drawings, the clothes washing machine 10there illustrated, is of the generally known spin-basket type. Moreparticularly, the machine 10 comprises a substantially rectangular base11 that is supported upon independently adjustable feet 12 arranged toengage the floor or other supporting surface. An enclosing housing orother casing 13 is removably carried by the base 11 and includes aconventional wraparound element including front, side and top walls. Thesides of the top wall 15 are substantially flush with the side walls ofhousing 13 to form an upright substantially rectangular prism. At therear of the top wall 15 is mounted a slightly vertically extendingbacksplasher 16 which serves as a control panel. The inner portion ofthis baoksplasher contains the control mechanisms and switches (shownonly as rectangle 16.1 for initiating a cycle of the proper length andtype. Purely by way of simplified example, there is shown a timercontrol knob 17 which is rotatable manually to set the desired length ofthe operative cycle.

A substantially centrally disposed stop opening 20 is provided in topwall 15 in order to render the interior of the housing 13 accessible. Aconventional lid 21 is provided for the purposes of selectively closingthe top opening 20'; the lid being hinged to top Wall 15 at its rearedge and movable thereabout from a closed position to an open positionallowing access to the interior of the casing 13 for loading orunloading the machine.

A generally rectangular collection chamber or drain tub 23 is providedin the upper portion of housing 13. The bottom wall 26 of chamber 23 iswelded or otherwise suitably sealed to the inner wall of the housing,and spaced above base 11 to define a machinery compartment 27 arrangedin the lower portion of housing 13. Within this compartment there isprovided a sup port structure 29 which serves as the foundation for thetransmission and this support is mounted to base 11.

This support structure 29 comprises a horizontal base plate 30, verticalside walls 31 extending therefrom to join a top plate 31.1 in forming anopen rectangular mounting space for the transmission mechanism 32.Secured to one side wall 31 is a curved channel member 35 towhich isbolted or affixed in any known manner the main drive motor 36. Motor 36is positioned in inverted fashion with its output shaft 3-6.1 dependingfrom the motor structure. Secured about the motor shaft is a coupling toa drain pump- (not shown) of any generally known type. The pump maypreferedly have its impeller fastened to the motor shaft so that thepump may expel waste water on rotation of the motor. Further, the motorshaft has mounted to it a pulley 37 which carries a flexible V belt 3-8.This V belt is also laced about large diameter pulley 39 of thetransmission mechanism 32, to impart a reduced speed driving eifectthereto. The transmission mechanism 32 is mounted in parallelrelationship to the motor 36 and has extending upwardly above itstopmost surface a central agitator shaft '45 which in its upward extentprotrudes through the bearing retainer structure and into the collectionchamber 23.

An upstanding spin basket 46 is centrally positioned within collectionchamber 23 and is mounted for rotation about a substantially verticalaxis. The spin basket is generally imperforate and has an open faceadjacent the top access opening of the casing 13 to allow access to thebasket interior. About the periphery of the basket adjacent the openface, there is secured an annular balance ring 46.1 of high densitymaterial providing a comparatively large moment of inertia for thebasket. The spin basket 46 is provided with an upwardly and outwardlyflared sidewall that terminates as mentioned below the access opening.Near its upper periphery basket 46 contains a horizontally alignedseries of apertures or slots 47 for centrifugally ejecting water fromthe basket. At the center of the spin basket there is positioned avertical agitator 48' which is mounted coaxially on the agitator shaft45 and is oscillated thereby. Also mounted coaxially to the agitatorshaft is a tubular spin shaft 49 whose upper end terminates a few inchesabove the spin basket lower surface. This spin shaft is used to impartrotative motion to the basket and to further this end, the spin shaft isfirmly secured to the spin tub 46 at hub 49.1. The lower end of spinshaft 49 is mounted securely to the upper surface of transmissionhousing 32 so that the spin shaft and basket are corotative with thetransmission housing 32. Exteriorly of the cylindrical body of theagitator 48 are positioned a plurality of radially extending agitatorvanes 50. The agitator is further provided with an outwardly and downWardly flared skirt '51 to which the vanes 50 are joined at their lowerends.

Turning now to the drive mechanism, there is provided as previouslymentioned, a main drive motor 36. The motor comprises a reversibleinduction motor of the split-phase type which may be of the two-speedtype, but for simplicity will be described herein as a singlespeedmotor. The motor, a typical appliance motor, has a rating of about /3horse power and an operating speed at full load of about 1,725 rpm. Themotor, ingenerally known fashion, may be energized through selectablecircuitry for rotation in the clockwise or counterclockwise direction toeffectuate the necessary agitate and spin operations.

In FIGS. 2, 3 and 4 there is shown a first embodiment of a brakemechanism employing my invention. This brake mechanism includes arotational brake housing 52 which confines a brake hand, laterdescribed. The housing structure is mounted on the transmission casing32 in the area above the upper exposed surface 54 of the casing. Thecasing includes a cylindrical vertical extension 55 protrusive above theexposed surface. This extension in turn is secured in any suitablefashion to the spin shaft 49 so that both structures rotatesimultaneously. Within this extension 55 there is provided a shoulder 56on which rests a metal bearing washer 57. This Washer serves as amounting base for the rotational mechanism 52. The housing 52 comprisesan irregular cylinder of metal such as steel with various indented areasforming cam surfaces therein. First, there is a low horizontal platformfined by the upstanding wall 62. As apparent from FIG. 2, wall 62spirals inwardly in opposition to the direction of rotation of shaft 49during the spin operation. The area above the platform and outwardly ofwall 62 const1tutes an opening in the brake housing. From a point (a)FIG. 2, which defines the limits of platform 64, an inclined plane orramp 66 spirals upwardly for an angular distance of 270 more or less,and terminates in a vertically and outwardly extending terminal wall 68.This terminal wall extends radially from intermediate wall 62 to theperipheral wall 69 of the structure 52, By this construction, theterminal wall 68 is angularly and axially spaced from the platform 64through the medium of the inclined plane 66 so that the approach to wall'68 from the plane of platform 64 is along the inelined ramp 66. Fittedinto the cylindrical brake housing is a metal brake band 70* which fitstightly against the inner wall 71 of the housing. This brake bandincludes a tang 72 extending radially from the band proper, andpositioned within a suitable notched area 73 within the wall structure74 of the brake housing. Also within the notched area 73, there ispositioned adjacent the tang 72 a suitable rubber cushion 75. Cushion75, by virtue of its position, will absorb a large portion of any shockstransmitted to either of these members. Bonded to the inner surface ofbrake band 70 is a brake lining 76 which optimally is constructed offriction material suitable for use in braking high inertia devices. Thisbrake lining is 64 of short radial depth as debonded to the interior ofthe band in such a manner that it fits tightly about the casingextension 55 so that the housing 5 2 will rotate with the casing andspin shaft 49 when the brake mechanism is maintained inactive, and thebrake band will impose a considerable braking force when the brakemechanism is activated.

Adjacent the brake housing 52 there is mounted as part of the totalbrake mechanism structure, a latch member 80 which extends horizontallyand tangentially toward the brake housing. A detent 82 extends radiallytoward the brake housing to enter into a latching relationshiptherewith, as presently explained. The latch member is pivotally mountedat the end most remote from detent 82. The pivotal mounting isaccomplished by means of a pivot rod 34 depending from the stationarytransmission support 311. About this rod there is mounted for freerotation a tubular bushing 86. At the bottom end of bushing 86 there isan annular flange 87 on which the latch member 85 rides. The flangerests freely on an expanded head of rod 84 and the flange and bushingare movable vertically on rod 84. A torsion spring 88 is coiled aboutthe bushing and has one spring end 88.1 anchored to a stationarymounting member 38.2. The opposite or lower end of the torsion spring88.3 is looped about the latch member to bias the latch member towardthe brake housing. The spring also biases the latch member toward itsflange 87. With this torsion spring and the mounting of bushing 86 onpivot rod 84, a limited amount of vertical travel of the bushing and itsattendant latch member is permitted. At the detent end of the latchmember there is connected a tension spring 90 which normally is inactiveand allows the detent to respond to the urging of the torsion spring 88and remain in the position shown in FTGS. 2. and 3. The remote end ofthe tension spring 91) is afiixed to the plunger 91 of a suit-. ableelectrically operated solenoid 92. Thus, when solenoid 92. is energizeddrawing plunger 91 into the solenoid proper, the tension spring 90 isactivated and overcomes the normal urging of torsion spring 88 and as aresult will draw detent 82 away from the brake housing.

To complete the structural description of the brake mechanism, as afurther component there is provided a top bearing washer 94 which restson the top of the casing extension '55 and serves to axially positionthe brake housing 52 with respect to the transmission casing whilepermitting one to rotate relative to the other. The brake housing wall62 is provided with a vertically extending groove 96 which extendsaxially from the plane of platform 64 to the top of the brake housing.This groove extends radially inwardly from the platform wallsubstantially to the brake band. The groove is recessed to a width anddepth sufiicient to receive detent 82 in a manner firmly locking thebrake mechanism to the latch member.

The Washing machine shown herein is of the conventional type whichthrough suitable control mechanisms governs the sequencing through awash cycle which includes a wash fill, a wash agitation period andextraction period followed by one or more rinsing cycles. Each rinsingcycle will, of course, consist of a rinse till, a rinse agitate periodand a rinse extract period.

To fully analyze the operation of the brake mechanism of the presentinvention, it is only necessary to view the operation during an agitateperiod and the subsequent extraction period, the other agitate and spinperiods being identical for the purposes of this invention. 'No'wviewing specifically the functioning of this embodiment during a washingmachine operation, it will be assumed that, after the preliminary stepsthe control mechanism has sequentially actuated the suitable componentsinto an agitating cycle. During an agitate cycle the drive motor 36 isimparting a clockwise (as viewed in FIG. 2) rotative force to the gearmechanism and as a result agitator shaft 45 is oscillated within thespin tube 49. The clockwise rotative force on the gear mechanism impartsa tendency toward sympathetic spin and oscillation on the transmissioncasing. 011 machines which utilize no positive braking apparatus, thetransmission casing tends to move with an action which can best bedescribed as oscillation superimposed on rotation, a speed which mayreach 13-15 rpm. This movement on such machines is transmitted throughthe spin shaft to the spin basket. The basket then describes thisoscillatory rotation which ends to impede the normal wash action and mayalso cause damage to the laundry in the basket.

During the agitate cycle on the present machine as equipped with apositive brake mechanism, the function of the brake mechanism during theagitate cycle is to hold the spin basket substantially stationary whilethe centerpost agitator oscillates. What is considered substantiallystationary is rotation on the order of 4 rpm. or less. In the agitatecycle, solenoid 92 remains deenergized and latch maintains its positionunder the normal urging of torsion spring 83-. Torsion spring 88, aspreviously mentioned, biases latch 80 toward the brake housing so thatdetent 8 2 is prepared for locking engagement therewith. If transmissioncasing 32 oscillates, and more particularly during the clockwise portionof the oscillatory movement, detent 82 will slidingly contact plat-form64 and will slide into engagement with groove 86 (as shown in FIG. 2).With this engagement, the brake mechanism will be anchored to the latchand the engagement of the brake band with the extension 55 will resist alarge proportion of the attempt at rotation or osci-llation.

As the control mechanism drives the machine elements into the extract orspin operation by suitable circuitry (not shown), solenoid 92 will beenergized and will draw its plunger in the direction away from the brakehousing. This plunger movement will draw latch member 80 away from thebrake mechanism. This plunger movement will overcome the contrary urgingof torsion spring '88- and will draw the latching detent '82 out ofgroove 96. The detent will thereby be held in a position out ofengagement with the brake mechanism as long as solenoid 92 remainsenergized. In the spin cycle the drive motor 36 will rotate the geartransmission casing through the belt and pulley system previouslydescribed and as a result casing 32 will rotate in the counterclockwisedirection as viewed in FIG. 2. The latch mechanism having been withdrawnfrom engagement with the brake mechanism, no impediments to rotation areencountered in the path of travel of the brake mechanism. Gear casing 32rotates and in turn rotates spin shaft 49 and spin basket 46 to extractliquid from the tub at a high rate of speed.

This unimpeded rotation continues until one of a number of conditionsoccurs. One of these conditions may be the conclusion of the timeallotted within the sequence for the extraction operation. Several makesof washing machines in present manufacture have a main power switch suchas 98, FIG. 1, which is held closed by the weight of the machine lid 21.In such machines, a second condition which may occur is that of themachine lid having been opened. An emergency condition may includeexcess gyra-tion of the basket actuating a shut-off mechanism. Thisarrangement, also, is well known in the art. Following any of theseoccurrences, the spin basket rotation should be terminated rapidly. Toeffect this stoppage of rotation, suitable generally known electricalswitches are actuated opening the energizing circuit to solenoid 92.

The circuitry shown in FIG. 9 is schematic, for all the necessarycomponents are old and well known. Timer-driver cam 10% is of thethree-level type, in which the lowest level closes cam follower 101against contact 102 to energize the reversible motor 36 in its spindirection; the upper cam level closes the follower against contact 103to energize the motor in its agitate direction; and the intermediatelevel establishes an open circuit condition. It will be apparent thatwhen the motor is in spin condition, an open lid switch 98 willdeenergize the motor and the solenoid 92. The lid switch has no suchcontrol when the motor is in agitate condition. When the cam 100 runsout the spin cycle and restores follower 101 to its intermediate level,both the motor and solenoid are deenergized. When solenoid 92 isdeenergized, latch 80 is under the control of torsion spring 83, whichimpels latch 80 in the direction toward the brake mechanism, detent 82then assuming a position adjacent brake housing 62. The brake housing,it must be remembered, is rotating in a counterclockwise directionduring this high speed extraction rotation. Further, it should beremembered that torsion spring 88 tends to maintain latch 80 and detent82 in a horizontal plane substantially as shown in FIG. 3. In thishorizontal plane detent 82 is positioned axially just above the level ofplatform 64. As detent 82 approaches the brake housing, either of twoconditions may occur during a rotation of the brake housing. In a firstof these conditions, the area of upstanding wall 69 may be found withinthe area to which the latch detent is impelled. If this conditionoccurs, the detent will strike the upstanding wall at its periphery, thedetent will slightly rebound from the wall and rotation will continue.As the brake housing continues through the same revolution, the inertialeffect of the latch mechanism having been deflected outwardly by therapidly rotating outer wall 69 will tend to maintain the detent at thesame radial distance from the drive shaft. This inertial effect will becontinued for a finite time period after the outer wall '69 hascompletely passed the detent. This period is sufficient to cause thebrake housing to have rotated groove 96 past the detent 82, alleviatingthe possibility of this engagement. As the brake mechanism continues itsrotation, detent 82 will be biased radially inwardly toward the centerof the rotating assembly and will encounter the open recessed area aboveplatform 64. In the area above the low platform 64, the detent will findlittle resistance to inward movement and will continue to move inwardlyuntil it strikes the inner wall 62 of the brake housing. The rotation ofthe brake mechanism continues and detent 82 will be guided upwardlyalong the rotating inclined plane 66. As the detent rides along thisramp surface, it is allowed further inward movement by the spiral wallof housing 62. At the top of this inclined ramp, detent 82 will finallybe guided into engagement with the radially extending wall 68. T heengage ment of the terminating wall and the latch detent immediatelyarrests rotation of the brake housing and braking force is transmittedfrom radial wall 68 through cushion 75 to tang 72 to band 70' andultimately through the brake lining 76 to the transmission casing 32. Itwill be evident that there is a slight relaxation of the brake band 70.This renders the braking action less abrupt, and reduces the shock loadwhich would otherwise be imposed on the casing 32. Nevertheless, thefrictional engagement of brake lining 76 with extension 55 brings thecasing 32 and its thereon mounted spin shaft to a stop.

Now turning back to the instant of engagement between the latch and thebrake mechanism, it should be noted that the torsion spring 88 nominallymaintains detent 82 in a plane just above horizontal platform 64. Whenthe contact between the detent and the wall 69 occurs in the area fromgroove 96 to radial line (a) approximately 90 away, the detent willenter the platform indentation, will contact wall 62 and ride up theramp. The slide action of bushing 86 on the pivot rod 84 follows theguided movement of the detent under the bias action of torsion spring 88by sliding up pivot rod 84 and moving the plane of the latch upin likeamount until terminal wall 68 is encountered' to initiate the brakingaction.

If however, the preliminary contact between the latch and the housingoccurs in the angular area from line (a) to the terminal wall '68, whichin the example shown in FIG. 2 encompasses about 225, the detent 82 willstrike the periphery 69 of the housing, which in this area is higherthan the plane of operation of the latch 80. The detent will thus berestrained outwardly of the housing until platform 64 has rotated to aposition adjacent the latch detent for contact therewith. As mentionedpreviously, within the area of platform 64 detent 82 will enter thebrake housing to contact wall 62. Slide motion of the latch up the rampwill follow leading to the brake action engagement. By thisconstruction, it is ensured that there is a contact of over 180 ofrevolution between the brake mechanism and latch before the brakingengage ment between detent 82 and radial terminating wall 68 is reachedto initiate the braking action.

A second embodiment of the brake mechanism is shown in FIGS. 58inclusive. The brake mechanism is quite similar to the prior embodimentgenerally and is mounted about gear casing extension 55a above andintegral to casing 32a. Casing 32, extension 55a, and spin tube 49a areall firmly afiixed to one another for rotation, as in the earlierdescribed embodiment. On the shoulder of the casing above exposedsurface 54a of casing 32a, there is mounted the brake housing which maybe described as a cylinder with a sloping upper wall surface or rampsurface 112, the development of which is shown in FIG. 7. Ramp 112 maybe considered as a cam surface which is radially level and extends froma low plane at line 114 to a high line at 116. In one direction the rampsurface extends from line 114 to line 116 for a distance of 270considered angularly, and in the other direction extends 90 from low tohigh. At the high position reached by line 116, a radially extendingtang 120 protrudes from an annular metal brake band 122 into a sizednotch in the inner edge of the upper surface at line 116. This tangextends radially only partially to the outer periphery 124 of the brakehousing 110. The brake band is of generally known incomplete tubularform as with the first described embodiment. Bonded to the inside of thebrake band is a brake lining 126 of suitable friction fabric which as inthe previous embodiment tightly encircles extension 5511 of the casing32. -A positioning annular washer 127 and suitable snap ring 128 ofextended vertical height may be used as a spacer and to position thebrake mechanism relative to the extension 55a and stationary support31a. This snap ring extends vertically from the top surface of the brakehousing substantially to the stationary adjacent support 31a as can beseen best in FIG. 6. As in the prior embodiment, the brake housing,brake band and lining rotate with the gear casing and spin tube on spinrotation in the counterclockwise direction, when no impediments torotation are encountered.

To provide the latching impediment to rotation when required, a latcharm 130 is pivotally secured to the adjacent support wall 31a at a pivotrod 132. On either vertical side of the connection of latch arm 139 tothe pivot rod, there is provided a rubber bushing, namely, 134 and 136,which combine to allow the latch member a limited amount of tiltingmovement in the vertical direction in addition to the pivotal motionabout rod 132. Latch member 130 (seen in detail in FIG. 8) includes astepped portion which horizontally spaces the mounting end 140 from thelatching end 142. Latching end 142 includes an inwardly concave section144 which substantially matches with the circularity of the outerperiphery of brake drum 122. Further along this inner latch surface, inthe direction toward its pivot axis, the latch end 142 is grooved at 146with a recess large enough to seat tang 120. Recess 146 and concavesection 144 are in the same horizontal plane within latch end 142. Withlatch arm 130 held horizontally, the plane of end 142 is at a lowerlevel than that of the pivot end 140. At this lower end, the latch arm130 is biased toward the brake mechanism by a tension spring 150anchored to any suitable stationary member such as an extension (notshown) of support 31a. Acting in the direction opposed to spring 158, isa link 152 which is secured to the latch arm adjacent groove 146 andextends from the opposite side thereof. This link is secured to theplunger 154 of solenoid 156 so that energization of the plungerwithdraws link 152 and latch 130 from possible contact with the brakemechanism. Solenoid 156 may physically be secured in any known fashionto the stationary structure 31a.

The operation of this embodiment is quite similar to the mode ofoperation of the prior embodiment. During the agitation portion of thiscycle, transmission casing 320: is oscillated sympathetically with butlittle power by oscillation of the center shaft 45a. Solenoid 156remains deenergized allowing spring 150 to advance the latch 130 towardthe brake mechanism. During the oscillation of the casing 320, concavesection 144 will at some time reach low area 114 and be drawn againstthe brake drum. With continuing oscillation, concave section 144 willride up the slope 1-12, presumably up the comparatively short 90 angularslope due to the prevailing clockwise rotation of the input to thetransmission and when the latch arm reaches high line 116 on the camsurface, tang 120 will engage with recess 146 and latch the brakemechanism to arm 130. In actuality, this action as described will occurinfrequently as the latch once having locked to the brake mechanism atthe conclusion of the last spin will maintain this engagement until thestart of the next spin operation.

With the start of spin, solenoid 156 is actuated, drawing its plunger154 inwardly and pulling link 152 to withdraw the latch from the braketo allow unimpeded counterclockwise rotation of the spin tube, gearcasing and casing extension. Solenoid 156 is held energized throughoutthe spin cycle and is deenergized by a signal indicating the end of spinperiod, unbalance, power loss, or by the opening of the lid controlswitch circuit, any condition of which signifies that the basketrotation is to be halted. With any one of these occurrences, solenoid156 is deenergized as the basket, transmission casing and spin tubecontinue to rotate at high speed. Engaging end 142 of the latch isreleased from the restraint imposed by the solenoid and is biased byspring 150 toward the brake housing in the plane adjacent the low spot114 on the cam surface. At all radial positions on the housing otherthan within a small area on either side of low area 114, concave section144- will strike the housing outer wall 124 and the rotation of thehousing will continue. When the low section 114 in the continuingrotation reaches an angular position adjacent the latch end 142, concavesurface 1-44 is allowed to penetrate the housing area and strikes brakeband 122. After this initial contact has been made, rotation of the spintube and brake housing continues as latch end 14-2 rides up the inclinedplane 112. As the rotation continues, tang 121 contacts the insetportion 160 of the latch 130. This contact of tang and inset leads thetang into latching engagement with groove 146. The latching engagementlocks the brake band 122 to the stationary structure through the latch.This has the effect previously noted: it slightly relaxes the brakelining 126 on the casing extension 55a to brake the casing Withoutimposing an excessive shock load. Nevertheless, because of thefrictional engagement of the brake band lining 126* with extension 55a,the spin tube and the basket come to a stop within a matter of seconds.This latch brake once engaged remains engaged until such time assolenoid 156' is energized, during spin only.

While there has been described what is at present thought to be thepreferred embodiments of the invention, it will be understood thatvarious modifications may be made therein, and it is the intention tocover all such modifications as fall within the true scope of theinvention.

What is claimed is:

1. A brake mechanism for a structure which includes a stationary supportand a rotor rotatable adjacent said support, comprising:

a cylindrical brake housing and band circumposed about said rotor,

a latching member pivotally secured to said support and biased towardsaid rotor in a plane perpendicular to the rotational axis of said rotorwhereby said brake housing arrests further pivotal motion of said memberand allows rotation of said rotor,

a recess of limited extent in said brake housing adjacent the pivotalplane of said member for receiving said member on pivoting thereof,

a cam surface spiralling about said housing from said recess forconducting said member therealong on rotation of said rotor followingreceipt of said member,

a contact shoulder spaced angularly and axially about said rotor fromsaid recess,

said contact shoulder extending radially from said brake housing at theend of said cam surface for stopping the conducted motion of said memberand engaging said member, means on said brake band responsive to saidengagement for actuating said brake band and for latching to said memberfor stopping rotation of said rotor.

2. A brake mechanism for a machine which includes a stationary supportstructure and a rotor mounted on said structure for rotation relativethereto, comprising:

a brake band disposed about said rotor in frictional engagementtherewith,

a housing about said brake band and engaging there- 'with for conjointrotation of said housing, brake band, and rotor, said housing having aramp spiralling upwardly thereabout,

a latch member pivotally secured to said support struc ture,

means for biasing said latch member for rotation toward said housing ina plane normal thereto and immediately above the low point of saidspiral ramp whereby said latch member may enter above said ramp only atthe low point thereof,

wall means extending radially of said ramp at the high point thereof forengagement by said latch member to interrupt rotation of said housingand brake band and thereby effect deceleration of said rotor,

and means for disengaging said latch member from said housing.

3. In a washing machine having a stationary frame structure, a spinbasket, and a motor for rotating said basket, the combinationcomprising:

a basket-rotating shaft adapted to be rotated by said motor,

a cylindrical brake housing disposed about said shaft for rotationrelative thereto,

a brake band fixed within said housing extending about said shaft infrictional engagement therewith, whereby said housing and said shaft mayrotate concurrently,

a latch member having a nose portion extending toward said housing,

means providing a ramp about the exterior of said housing, said ramphaving a low point immediately below the plane of said latch member andspiralling upwardly about said housing to terminate in a radiallyextending wall structure,

means for mounting said latch member for displacement in a first planenormal to the axis of rotation of said housing and in a second planeparallel thereto,

and means for effecting displacement of said latch member in saidfirst-named plane to engage with said housing in surface contact withsaid ramp, whereby rotation of said housing relative to said latchmember ultimately effects engagement of said housing wall structure withsaid latch member and consequent interruption of rotation of saidhousing and deceleration of said shaft.

4. In a washing machine having a stationary frame, a spin basket, and amotor for rotating said basket, the combination comprising:

a basket-rotating shaft adapted to be rotated by said motor,

- a brake supporting structure disposed about said shaft for rotationrelative thereto,

. a brake bandfixed within said supporting structure extending aboutsaid shaft in frictional engagement therewith, whereby said brake bandand said shaft may rotate concurrently,

a latch member having an end portion extending toward said supportingstructure,

means providing a ramp about the exterior of said supporting structure,said ramp having a low point immediately below the plane of said latchmember and spiralling upwardly about said supporting structure,

means at the top of said ramp engageable by said latch member endportion to interrupt rotation of said brake band,

means for mounting said latch member for displacement in a plane normalto the, axis of rotation of said housing, said mounting means providingfor movement of said latch member end portion axially of said supportingstructure,

means for efiecting withdrawal of said latch member relative to saidhousing,

and means ttor effecting displacement of said latch member in its saidplane to engage the latch mem ber end portion with said housing insurface contact with said ramp, whereby rotation of said housingrelative to said latch member ultimately bring said end portion intooperative association with said brake hand to interrupt rotation thereofand effect deceleration of said shaft.

5. In a washing machine having a stationary frame, a spin basket, and amotor for rotating said basket, the combination comprising:

a basket-rotating shaft adapted to be rotated by said motor,

a brake supporting structure disposed about said shaft for rotationrelative thereto,

a brake band :carried by said structure and encircling said shaft infrictional engagement therewith, whereby said structure and said shaftmay rotate concurrently,

a latch member having an end portion extending toward said structure,

.means providing a ramp on said structure, said ramp having a low pointimmediately below the .plane of said latch member and spiral-lingupwardly about said structure, said brake band having a radiallyextending end wall defining the uppermost end of said ramp, 7

means for mounting said latch member on said frame for displacement in aplane normal to the axis of and means for eifecting displacement of saidlatch member in its said plane to engage the latch end portion with saidhousing in surface contact with said ramp, whereby rotation of saidhousing relative to said latch member ultimately effects engagement ofsaid brake band end wall with said latch memher and consequentinterruption of rotation of said brake band and deceleration of saidshaft.

. 6. in a washing machine having a stationary frame, a spin basket, anda motor operable in either forward or reverse direction, the combinationcomprising:

a basket-rotating sha ft adapted to be rotated by said motor,

a cylindrical brake housing disposed about said shaft for rotationrelative thereto,

a brake band fixed within said housing extending about said shaft infrictional engagement therewith, whereby said housing and said shaft mayrotate concurrently,

a latch lever having a nose portion extending toward said housing,

means providing a ramp on said housing, said ramp having a low pointimmediately below the plane of said latch lever and spiralling upwardlyabout said housing to terminate in a radially extending wall structure,

wall means providing a detent pocket in said housing on the level of thelow point of said ramp,

means for mounting said latch lever for displacement of the nose portionthereof in a first plane normal .to the axis of rotation of said housingand in a second plane substantially axially of said housing,

a solenoid mechanically associated with said latch lever,

electric circuit means for energizing said solenoid to withdraw saidlever from said housing upon concurrently energizing said motor =foroperation in one, only, of said motor operating directions,

and spring means efiective upon concurrent deenergization of said motorand solenoid to move said lever to bring the nose thereof for engagementwith said detent pocket or into overlying relation with said rampaccording to the angular displacement of said pocket relative to saidnose at the time of such lever movement, whereby maximum delay ininterruption of rotation of said housing is represented by the timerequired for said nose to traverse said ramp and engage with the radialwall means defining the end thereof.

References Cited in the file of this patent UNITED STATES PATENTS279,033 Smith June 5, 1883 962,141 Hartmann June 21, 1910 1,788,110Junghans Jan. 6, 1931 2,807,951 Gerhardt et al. Oct. 1, 1957 2,946,409Jennings July 26, 1960

1. A BRAKE MECHANISM FOR A STRUCTURE WHICH INCLUDES A STATIONARY SUPPORTAND A ROTOR ROTATABLE ADJACENT SAID SUPPORT, COMPRISING: A CYLINDRICALBRAKE HOUSING AND BAND CIRCUMPOSED ABOUT SAID ROTOR, A LATCHING MEMBERPIVOTALLY SECURED TO SAID SUPPORT AND BIASED TOWARD SAID ROTOR IN PLANEPERPENDICULAR TO THE ROTATIONAL AXIS OF SAID ROTOR WHEREBY SAID BRAKEHOUSING ARRESTS FURTHER PIVOTAL MOTION OF SAID MEMBER AND ALLOWSROTATION OF SAID ROTOR, A RECESS OF LIMITED EXTENT IN SAID BRAKE HOUSINGADJACENT THE PIVOTAL PLANE OF SAID MEMBER FOR RECEIVING SAID MEMBER ONPIVOTING THEREOF, A CAM SURFACE SPIRALLING ABOUT SAID HOUSING FROM SAIDRECESS FOR CONDUCTING SAID MEMBER THEREALONG ON ROTATION OF SAID ROTORFOLLOWING RECEIPT OF SAID MEMBER, A CONTACT SHOULDER SPACED ANGULARLYAND AXIALLY ABOUT SAID ROTOR FROM SAID RECESS, SAID CONTACT SHOULDEREXTENDING RADIALLY FROM SAID BRAKE HOUSING AT THE END OF SAID CAMSURFACE FOR STOPPING THE CONDUCTED MOTION OF SAID MEMBER AND ENGAGINGSAID MEMBER, MEANS ON SAID BRAKE BAND RESPONSIVE TO SAID ENGAGEMENT FORACTUATING SAID BRAKE BAND AND FOR LATCHING TO SAID MEMBER FOR STOPPINGROTATION OF SAID ROTOR.